Write blog post introducing and describing the new process

[gregsdennis]

@jdesrosiers wrote an intro post regarding the move away from IETF and the direction we're heading from the point of view of increasing stability.

We need another post that describes the new SDLC in more detail. This will be the public-facing equivalent of #1333.

[gregsdennis]

Post should reflect the decisions described in https://github.com/orgs/json-schema-org/discussions/671 and #1444